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Magnesium to replace lithium as battery material

January 04, 2019 By Christoph Hammerschmidt

The E-Magic research project aims to develop batteries that are more powerful, cheaper and safer than the widespread lithium-ion battery. This project focuses on novel magnesium-based batteries. The research project, funded by the European Union (EU) with over 6.5 million euros, brings together the activities of various European scientific institutions, including the Karlsruhe Institute of Technology (KIT), the University of Ulm (Germany) and the German Aerospace Center DLR.

According to the scientists, magnesium batteries should have decisive advantages over conventional lithium-ion batteries: Magnesium as an anode material enables a higher energy density and would also be much safer in the event of a fire. "Magnesium is a promising material and one of the most important candidates for our post-lithium strategy," says Professor Maximilian Fichtner, Deputy Director of the Helmholtz Institute Ulm (HIU) , a research institute founded by KIT in cooperation with the University of Ulm and the associated partners DLR and ZSW to research and develop electrochemical battery concepts. "A broad availability of magnesium batteries could decisively advance the electrification of mobility and the expansion of decentralised home storage systems. In order to accelerate the development of this new type of battery, the HIU is now cooperating with other scientific institutions in the field of battery and materials research in the European Magnesium Interactive Battery Community (E-Magic) research project.

In the project, the partners combine all necessary steps for the development of magnesium batteries, from basic research to cell production processes. The main aim of the scientists is to contribute to understanding the obstacles and challenges at the materials level and to create new solutions for current obstacles. "The special challenge with magnesium batteries is a long service life," explains Dr. Zhirong Zhao-Karger, who coordinates the activities of the new research project in the Solid State Chemistry Research Group at HIU. However, there are a number of positive properties of the new battery material that the researchers want to use: for example, no dendrites form on the magnesium anodes. In lithium-ion batteries, such electrochemical deposits on the electrodes can form needle-like structures and cause disturbances or even dangerous short circuits. There are no comparable processes in magnesium. It is therefore possible to use magnesium in metallic form and thus directly utilize the high storage capacity of the metal.

In addition to greater safety and energy density, the introduction of magnesium technology in battery production could also help to reduce dependence on lithium as a raw material: as an element, magnesium is around 3,000 times more abundant on earth than lithium and, in contrast, is much easier to recycle. Accordingly, magnesium batteries would also be cheaper than lithium-ion batteries. If Europe makes rapid progress in development, magnesium batteries could also help to reduce the dominance of Asian producers of battery cells and establish competitive battery production in Europe.

European Magnesium Interactive Battery Community


Start date 1 January 2019 / End date 31 December 2022

Objective
Energy storage is a key technology to facilitate a widespread integraWith the growing use of intermittent energy sources in power grids, there is a growing mismatch between when energy is produced and when it is consumed. This has led to the need of energy storage or demand-response systems in order to use the energy in a balanced and efficient way. Given this context, the Micro Energy Storage (MES) systems are expected to seek radically new approaches to supply energy where it is needed. Buildings are becoming a local use micro energy-hubs consuming, producing, storing, supplying energy and having the potential to take up an important role in the power-supply system stability which generate energy with renewables, provide storage for electric and thermal energy and deliver demand response. For Micro Energy Storage in Buildings (MESB) using stochastic renewables energy, the most suitable technology is the lithium-ion batteries (LIB). However, current LIB technologies are facing severe challenges in safety, energy density and price. While most of today's R&D is concentrated on LIB systems, shifting towards non-lithium rechargeable batteries may open up effective ways to overcome such challenges. The rechargeable magnesium battery (RMB) constitutes a paradigmatic example of such promising, alternative non-lithium energy storage systems, following pioneering efforts and breakthroughs from world-wide researchers. The potential to use metallic magnesium anodes in rechargeable batteries brings important advantages in terms of energy density, cost and safety. E-MAGIC gathers the key scientific and technical researchers in Europe to develop the required new frontier knowledge and foundational approaches on RMB, bringing an effective work on R&D by a rational design of high voltage/high capacity cathode materials and novel electrolytes to overcome the rate-limiting reaction and transport processes, in order to deliver a safe RMB with more 400 Wh kg-1 and less than 100 €/Kwh.

Researchers at DOE's Lawrence Berkeley National Laboratory (Berkeley Lab) and Argonne National Laboratory were working on a magnesium battery, which offers higher energy density than lithium, but were stymied by the dearth of good options for a liquid electrolyte, most of which tend to be corrosive against other parts of the battery. "Magnesium is such a new technology, it doesn't have any good liquid electrolytes," said Gerbrand Ceder, a Berkeley Lab Senior Faculty Scientist. "We thought, why not leapfrog and make a solid-state electrolyte?"

The material they came up with, magnesium scandium selenide spinel, has magnesium mobility comparable to solid-state electrolytes for lithium batteries. Their findings were reported in Nature Communications in a paper titled, "High magnesium mobility in ternary spinel chalcogenides." JCESR, a DOE Innovation Hub, sponsored the study, and the lead authors are Pieremanuele Canepa and Shou-Hang Bo, postdoctoral fellows at Berkeley Lab.


Read more at: https://phys.org/news/2017-11-holy-grai ... m.html#jCp

Can Magnesium Do Lithium's Job ?

New cathode and electrolyte materials might let magnesium provide an alternative to lithium in high performance battery systems.

January 04, 2019

Magnesium (Mg) has several advantages over lithium for battery applications. Each magnesium atom releases two electrons during the battery discharge phase, compared to one electron for lithium. This gives it the potential to deliver nearly twice the electrical energy than what is possible from a lithium cell. In addition, magnesium does not grow dendrites on the metal surface during the battery charging phase. The spiky dendrite crystals that grow on a lithium metal surface can cause dangerous short-circuiting of the battery. The lack of dendrite growth should make magnesium batteries easier to handle and safer. Lastly, magnesium is more common and readily available than lithium. The USGS reports that it is the eighth most abundant element and can be commercially extracted from mineral deposits or seawater.

Needs More to Be Competitive

According to Yan Yao, associate professor of electrical and computer engineering at the University of Houston (UH), magnesium batteries won’t be commercially competitive until they can store and discharge large amounts of energy. Previous cathode and electrolyte materials have been a stumbling block. The problem is that magnesium reacts with conventional carbonate electrolytes to create a passivating layer on the surface of the metal that acts as a barrier and prevents magnesium ions from reaching the magnesium metal during charging.

Yao led a team of researchers who examined both the cathode and the electrolyte materials in an effort to improve magnesium battery performance. “Through (the) optimal combination of organic carbonyl polymer cathodes and Mg-storage-enabling electrolytes, we are able to demonstrate high specific energy, power, and cycling stability that are rarely seen in Mg batteries,” the team said in a UH news release.

New Organic Cathodes

Yanliang Leonard Liang, research assistant professor at UH, noted that until now, the best cathode for magnesium batteries has been a Chevrel phase molybdenum sulfide, developed almost 20 years ago. Chevrel phases are clusters of atoms that have been extensively studied because they can act as superconductors. But the Chevrel phase molybdenum sulfide, when used as a magnesium battery cathode, has neither the power nor the energy storage capacity to compete with lithium batteries, Liang said in the news release. Recent reports suggested that new organic cathode materials could provide higher storage capacity at room temperature, so this was a direction the UH team decided to follow. Indeed, both organic polymer cathodes tested by the researchers provided higher voltage than the Chevrel phase cathode.

New Electrolyte

In addition, Yan Yao said the researchers were able to confirm that chloride in the commonly used electrolyte contributed to sluggish performance. “The problem we were trying to address is the impact of chloride,” he said, adding, “It’s universally used.” Yao’s team used the chloride-free electrolyte to test organic quinone polymer cathodes with a magnesium metal anode and reported in the news release that, “they delivered up to 243 watt hours per kilogram, with power measured at up to 3.4 kilowatts per kilogram. The battery remained stable through 2,500 cycles.”

Yao indicted that future research will focus on further improving the specific capacity and voltage for the batteries in order to compete against lithium batteries. “Magnesium is much more abundant, and it is safer,” he said. “People hope a magnesium battery can solve the risks of lithium batteries.”

Senior Editor Kevin Clemens has been writing about energy, automotive, and transportation topics for more than 30 years. He has masters degrees in Materials Engineering and Environmental Education and a doctorate degree in Mechanical Engineering, specializing in aerodynamics. He has set several world land speed records on electric motorcycles that he built in his workshop.

Since magnesium is heavier than lithium, the battery will naturally be heavier for a given energy capacity. Indeed, the theoretical energy density of a magnesium-ion battery is 2205 mAh/g compared to 3861 mAh/g for lithium-ion. However, in practicality, lithium-ion batteries are achieving less than 150 mAh/g. Early tests have shown that with a sulfur cathode, a magnesium-ion battery can achieve 1000 mAh/g

Removing Barriers to Commercialization of Magnesium Secondary Batteries